In arc welding, such as for example an orbital welder, a welder power supply is used that produces a low voltage high current power source to maintain a stable arc. The arc is initiated or struck by a high voltage breakdown across the gap between the electrode and the workpiece. Once the arc is struck, the voltage across the gap is much lower than the breakdown voltage and the current increases substantially. An arc start circuit may be used to strike the arc, and then the welder power supply is used during the welding operation.
Arc start circuits are generally either AC or DC. The present disclosure is directed to a DC arc start circuit. Known DC arc start circuits are designed for particular input voltage specifications. If the input voltage changes, a new model power supply with the appropriate input range must be selected to operate using the new input voltage, otherwise an incorrect output voltage is produced, or in some cases the DC arc start circuit can only work with a single input voltage.
Summary
In accordance with one inventive aspect of the disclosure, a DC arc start circuit is contemplated that is autoranging. As used in this disclosure, autoranging refers to a circuit performance that produces a stable and repeatable output over a wide range of input voltage. The arc start circuit operates effectively as a universal input power supply. In one embodiment, a DC arc start circuit includes an autoranging or universal input DC power supply that converts an AC or DC input source to a first DC voltage. The DC arc start circuit further includes a DC to DC converter that receives the first DC voltage and increases it to a second DC voltage of a value that is sufficient to reliably start or strike an arc. Other inventive aspects of the disclosure include a welding system that uses an autoranging DC arc start circuit, as well as methods for producing an arc start voltage with a universal input supply.
These and other aspects and advantages of the disclosure and inventions herein will be readily understood and appreciated from a reading of the following detailed description in view of the accompanying drawings.